Chipset shrinks for high-current conversion

An International Rectifier product story

Edited by the Electronicstalk editorial team Sep 12, 2003

A compact control and synchronous MOSFET chipset aims for applications in VRM10.x high-current synchronous buck convertors.

International Rectifier has introduced the smallest control and synchronous mosfet chipset for existing and next-generation VRM10.x high-current synchronous buck convertors where small size, high efficiency and maximum thermal conduction are mandatory.

The IRF6608 control mosfet has 8.5mohm typical on-resistance, whereas the IRF6618 synchronous mosfet has 1.7mohm typical on-resistance.

The new devices are housed in the DirectFET package.

The IRF6608 is 50% smaller than the standard SO-8 package, and is the first HEXFET mosfet housed in the new double-side-cooled, surface-mount DirectFET S package.

The profile is 0.7mm, compared with 1.75mm for an SO-8.

In addition, the new IRF6608 has as much as 10% better on-resistance, reduced gate charge and gate-to-drain charge characteristics compared with similar control mosfets on the market, delivering over 2% more overall efficiency, making it an ideal control mosfet.

The IRF6618 has a typical on-resistance of 1.7mohm and a maximum of 2.2mohm, a 25% improvement compared with similar devices on the market, and is ideal for the synchronous mosfet application, where low conduction loss is most important.

The IRF6618 can also be used for secondary side synchronous rectification in high-current isolated DC/DC convertors.

The new chipset enables designers to make a very low profile power convertor (0.98in) for 1U (1.75in height) rack sized server systems that meet VRM 10.x specifications.

The new chipset is also suitable for buck convertors in servers and point-of-load convertors in telecomms and networking systems.

Carl Blake, International Rectifier Marketing Manager for the Computing and Communications Business Unit said: "The new IRF6608 and IRF6618 mosfets in the DirectFET package give circuit designers a revolutionary new tool in the battle to remove heat in tiny spaces, while increasing efficiency and current-handling capability".

The new DirectFET mosfets are available immediately.

Pricing for the IRF6608 is US $1.03 each and the IRF6618 is US $1.52 each in 10,000-unit quantities.